i had almost exactly the same experience. my pain was in the same area, l4-5, s1. i had rewached the point where i could only walk shor distances, very painfully, with a walker and was seriously considering a wheel chair. i talked to my dr (who is as much a friend as a dr) who referred me to a do who specializes in spines. bottem line, i had a laminectomy in 2002 and was vitrtually pain free for about a year. then the pain came back and kewpt getting worse. i went back to the surgio0n who suggested another operration to tske the screws out of the titanium rod holding my spine together. after this operation i could walk again without a cane for short distances and with a cane if i have to do walmart. i am also goinf to a pain management dr and am taking 3 percodet/day, 2 flexeril/day, and morphine for breakthrough pain (up to 3/day).
i'm not doing swimmingly, but it beats the devel out of the alternative. by the way, once you've had back surgery, no chiropracter will touch your back.
hope this helps.
That light at the end of he tunnel? It's an on-coming train.